Electron beam register signaling system



March 9, 1954 Q, SOFFEL 2,671,824

ELECTRON BEAM REGISTER SIGNALING SYSTEM Filed Dec. 2, 1949 3Sheets-Sheet 1 KEYSET I CIRCUIT 2 P22 REGISTER REG/S TER SENDER 100SWEEP CIRCUIT SWP/ INVENTOR R. 0. 50F F E L AT TORNEY March 9, 1954 R.o. SOFFEL ,67 ,8

ELECTRON BEAM REGISTER SIGNALING SYSTEM Filed Dec. 2, 1949 3Sheets-Sheet 2 INCOM/NG JUNCTOR 30 [-76 2 60 6/ meow/vs L LINE CHOICE 0CONNECTOR REGISTERS TERM/NATING REGISTER SEA/OER 200 GATE CIRCUIT SWEEPcmcun SWPZ IN [/5 N TOR R. 0. SOFFEL AT TORNE V March 9, 1954 Q SQFFEL2,671,824

ELECTRON BEAM REGISTER SIGNALING SYSTEM Filed Dec. 2, 1949 3Sheets-Sheet 3 DIG/7' REGISTER RELAYS Fla. 4 DIG/T REGISTER RE 6 IS TERSTO OTHER 0/6] T REG/S TERS o OTHER REGISTERS lNl/ENTOR R0. 50F FE L mam.

Patented Mar. 9, 1954 ELECTRON BEAM REGISTER SIGNALING SYSTEM Robert 0.Sofiel, Hastings-on-Hudson, N. Y., assignor to Bell TelephoneLaboratories, Incorporated, New York, N. Y., a corporation of New YorkApplication December 2, 1949, Serial No. 130,687

5 Claims. 1

.This invention relates to signaling and in particular to signalingsystems suitable for use in transmitting a plurality of letter andnumerical digits corresponding to telephone directory or other routingnumbers for controlling the establishment of desired communicationconnections in telephone systems.

Objects of the invention are the rapid and accurate transmission ofletter and numerical digits over interoffice trunks in automatictelephone systems, the synchronization of the signal transmitting andreceiving means, and the transmission of signals back over a trunk toindicate that the signals have been received or that the signals shouldbe repeated.

This invention is exemplified in a two-way signaling arrangementcomprising like electron beam multitarget tubes connected to the ends ofan interconnecting signal transmitting medium or channel.

A feature of the invention is a signaling arrangement in which anelectron beam tube connected to one end of a trunk transmits codedletterand digit signals over a trunk to a similar electron beam tube.Another feature of the invention is the transmission of a startingimpulse from the digit sending tube to the'digit receiving tube at thebeginning of a series of signals to synchronize the sending andreceiving tubes, the beam of both tubes being normally focussed on aparticular electrode which constitutes a start position for each sweepof the beam. Another feature of the invention is the transmission of anend impulse from the digit sending tube after all of the letter andnumerical digits have been sent. Another feature is the transmisson of areorder signal impulse from the digit receiving tube to the digitsending tube if any received digit signal appears to be incomplete orincorrect and the transmission of a difi'erent signal if all receiveddigit signals appear to be complete and correct.

A clear and complete description of these and other features of theinvention will be facilitated by referring to the telephone system andsignaling arrangement disclosed schematically in the drawing whichconsists of four figures. Referring to the drawing:

Fig. 1 shows in a first central ofiice a subscriber station l and lineii, an operator position comprising a cord [5 and a position circuit 16including a key-set, an outgoing trunk circuit 20 connected'to one endof a. trunk T, and a register-sender lll'fl for registering the numberkeyed by an operator and for controlling the transmission of theregistered number over the trunk T;

Fig. 2 shows in a second central oflice comprising automatic switchingequipment of the cross bar type, an incoming junctor 30 individual tothe trunk T, an incoming link 50, a line choice connector 50, asubscriber line 8! and station '60 and a terminating register-sender200;

Fig. 3 shows one of the four sets of digit registering relays in theregister-sender Hi0 arranged for controlling th transmission of digitsignalsby the tube i H) in this sender; and

Fig. 4 shows one of the four digit registers in the register-sender 20$)arranged for controlby signals received by the tube 2) in this sender.

The subscriber station it) may be of known type and be connected by lineI l to a manual or automatic type local central ofiice which is notshown in the drawing. The jack I2 terminates an incoming trunk from thelocal central ofiice at .a toll operator position It equipped withaplurality of cords It for answering and extending calls and. with aten-key numerical key-set which is used when the call is being extendedover an outgoing trunk to an automatic type central ofiice. One suchoutgoing trunk T is shown, the associated outgoing trunk circuit 20being connected to a jack I! at the toll operator position 16. The trunkcircuit 20 is shown schematically including the talking transmissionpath, the conductors 2i and 22 through which key pulsing signals .aretransmitted from the operator key-set to be registered in aregister-sender Hi0, and the conductors 25 and 26 through whichselective signals are transmitted over the trunk T to the automaticcentral ofiice to register the called number in that office. Referencemay be had to Patent 1,916,760, granted July 4, 1933, to I. H. Henry fordescription of the operator key-set and outgoing trunk circuits and alsofor description of a link circuit (not shown) through which the trunkcircuit 20 is connected to an idle register-sender circuit Hi8 when acord 15 is connected with jack H. The conductors 2| 2 2, 25 and 2.6correspond to conductors 3H, 3I3, 3ll6 and 3.08 respectively of thetrunk circuit shown in Fig. 3 of the Henry patent. The register-senderN10 is a modification of the register-sender shown in 'the Henry patent.The registers I05, I06, In]

and H38 are similar to the thousands, hundreds, tens and units registersin the Henry patent and are set under the control of the operatorkey-set in similar manner to that described for the correspondingregisters in the Henry patent; (and Fig. 3 shows the register relays,which are provided for each register, with contacts arranged to controlthe sending of any digit registered.

The four register relays Ri R2, R4 and R5 are of the known additiveindication type, relay RI being operated to register the digit one,relay R2 to register the digit two, relays RI and R2 both being operatedto register the digit three and so on.

The automatic local central oflice in which the trunk T terminates isshown as being of the cross bar type, the trunk T being connected to anincoming junctor 30. The incoming junctor 30, incoming link 40 and linechoice connector 50 are not shown in complete detail but reference maybe had to Patent 2,089,921 granted to W. W. Carpenter August 10, 1937,for a complete disclosure of similar cross bar type switching equipment.In the Carpenter patent an incoming junctor is shown in Fig. 58 and anincoming link and connector are shown in Fig. 57. Relay 580I of incomingjunctor corresponds to the like identified relay in the Carpenterpatent. The conductors 3| and 32 correspond to conductors 5826 and 5825respectively of the incoming junctor shown in Fig. 58 of the Carpenterpatent and transmit the selective signals incoming over trunk T to aterminating register-sender 200 which is associated by a link circuit(not shown) with the incoming junctor upon seizure of trunk T byconnection of a cord I5 to jack I! in the toll ofiice. Theregister-sender 200 is a modification of the terminating senderdisclosed in Figs. 29, 30 and 37 of the Carpenter patent and includesregisters 205, 206, 20'! and 208, the settings of which are used by aterminating marker (not shown) in the manner described in the Carpenterpatent to control extension of connections through links 40 andconnectors 50 to called subscriber lines.

The register-senders I and 200 are arranged for selective signaling inaccordance with applicants invention instead of in the manner describedin either of the aforementioned Henry and Carpenter patents, and thesignaling means in each of these register-senders is shown and describedherein in detail. A multitarget electron beam tube is provided in eachof the senders, the tube IIO of register-sender I00 being effective totransmit the called number over trunk T under the control of registersI05, I06, I01 and I08; and the tube 2I0 of register-sender 200 beingoperatively responsive to th digit signals incoming over trunk T to setthe registers 205, 206, 207 and 208, each of which is similar to theregister shown in Fig. 4. The tube H0 in register-sender I00 comprisesan evacuated enclosing vessel having at the right end a cathode I I2,cathode heating filament III, and a beam forming and accelerating anodeH3. The concentrated electron beam passes out through the aperture H4 ofanode II3 toward the left and centrally between deflection plates I I5through apertures in a shield electrode II6 to engage the target anodesmounted at the left end of the tube. The mounting of the vari-- ouselements within the evacuated vessel and the leading-in conductors arenot shown; but reference may be had to Patent 2,452,157, granted to R.W. Sears, October 26, 1948, for a complete disclosure of the structureof such a tube. Each of the target anodes is made of, or is coated with,a material which readily emits electrons when energized by the electronbeam; and the shield electrode H6 is maintained at a positive potentialwith respect to each of these anodes so as to act as a collector of theelectrons emitted from the target anodes. The tube is normally biased sothat the beam is engaging the start anode I20. A linear sweep circuitcomprising tubes I 40, I50, I60 and H0 controls the movement of the beamto step from the start anode I20 and successively engage each of twentyintermediate anodes, the potential of which is controlled by registersI05, I06, I01 and I08, an end-of-code anode I25 and a reorder anode I26and to then return to and rest on the start anode I20. The twentyintermediate anodes form four groups I2I, I22, I23 and I24 of fiveanodes each. The anodes a, b, c, d and e of group I2I are connected tothe thousands digit register I05, as shown in Fig. 3; the anodes a, b,c, d and e of group I22 are connected to the hundreds digit registerI06, the anodes a, b, c, d and e of group I23 are connected to the tensdigit register I01; and the anodes of group I24 are connected to theunits digit register I08. A start circuit comprising thermionic tube I30controls the starting of the operation of sweep circuit SWPI when theregisters have been set; and an advance or reorder circuit comprisingvacuum tube I responds to an advance signal to effect release of theregister-sender I00 and responds to a reorder signal received over trunkT to efiect the starting of the sweep circuit to repeat the sending ofthe code corresponding to the set registers in case the coded digitsignals are not properly received and registered in the cross baroffice.

The tube 2I0 in register-sender 200 is similar in structure to that oftube H0 and reference numbers of corresponding elements have the sametens and units digits. The tube is normally biased so that the electronbeam tube is engaging the start anode 220. The linear sweep circuit SWP2comprising thermionic tubes 240, 250, 260 and 2'10 controls the movementof the electron beam to step from the start anode 220 and successivelyengage each of twenty intermediate target anodes, an end-of-code anode225 and a reorder anode 226 and then back to rest on the start anode220. The twenty intermediate target anodes form four groups of fiveanodes each. The anodes a, b, c, d and e of group 22I are connected tocontrol the operation of the thousands digit register 205 as shown inFig. 4; the anodes a, b, c, d and e of group 222 are connected tocontrol the operation of the hundreds digit register 206; the anodes a,b, c, d and e of group 223 are connected to control the operation of thetens digit register 201; and the anodes a, b, c, d and e of the group224 are connected to control the operation of the units digit register208. A gate circuit comprising thermionic tubes 230, 280 and 290controls the resetting of the registers and each register controls thesending of an advance or a reorder signal over trunk T depending uponwhether each of the registers is operated to indicate receipt of acomplete and correct code.

The further explanation of the operation of the system will befacilitated by assuming that a call is originated at subscriber stationI0 and that the called station is station 60 in the cross bar oflice.Assume further that the line II of station I0 has been connected byswitching means, not shown, to the jack I2 in the toll office and by acord I5 and jack I! to outgoing trunk circuit 20, that a register senderI 00 has been connected to trunk circuit 20, and that the tolloperator's key-set I6 has been operated to transmit key-set signals overconductors 2I and, 22 to set the thousands, hundreds, tens and unitsdigit registers I05, I 06, I01 and I08 in the manner described in theaforementioned Henry patent. Assume further that the number thusregistered is the number I319, as described in the Henry patent.whereby, in register I05, relay RI is actress operated; register I06,relays RI and R2 areoperated; in register I 'I-, relays R2 and R areoperated; and, in register I08, relays R4- and R5 are operated. When theregister-sender I00 is connected to trunk circuit 23, the windings ofrelays 6I0 and BIB (which correspond to like identified relays in theaforementioned Henry patent) are connected in series through conductors25 and 26 across the conductors of trunk T, thereby constituting aseizure signal which effects the operation of relay 5302' of incomingjunctor circuit 30, thereby to extend the trunk through conductors 3|and 32 and a link circuit (not shown) to an idle register-sender circuit200- in the manner described in the aforementioned Carpenter patent.Relays 6H5 and 6I9 are polarized. in opposite directions, relay BISbeing operated at this time and relay 6I8'remaining non-operated. Theoperation of relay 6I9 performs no useful function at this time. When anidle register-sender 200 is seized and connected to junctor 30, a relayI in the registersender (which relay corresponds to relay 3700 in theCarpenter patent) and relay 5801 of the junctor are operated in themanner described in the Carpenter patent, thereby connecting trunk Tthrough conductors BI and 32 to the left winding of coil 202. The trunkT is thereby inductively connected to the shield electrode of signaltube H0, at the same time causing the operation of polarized relay BISand release of relay 6I9 of register-sender I00. The coil 202 andwindings of relays (H0 and 5I9 are designed so as not to initiatetransients which might effect the starting of sweep circuit SWPZ. Theoperation of relay SIB closes a circuit for operating relay IOI. RelayI'0I locks independently of relay 0I8 under control of relay I99 andconnects the conductors of trunk T through conductors and 26 to the leftwinding'of coil I02 whereby a signal transmitting path is inductivelycompleted between trunk T and the shield electrode IIB of tube IIO. Whenthe registers I05, I06, I01 and I08 have been set by key pulsing signalsfrom the operator key-set and relay SIB has operated to indicateconnection of trunk T to a register-sender 200 in the terminatingoffice, a circuit is closed for operating start relay I09. When relayI09 operates, it connects battery B3 to conductor I29 of registers I05,I06, I01 and I08. With relay RI operated in register I05, this positivebattery potential is connected to anodes a and d in group I2I; withrelays RI and R2 operated in register I06, the positive potential isconnected to anodes d and e in group I22; with relays R2 and R4 operatedin register I01, the positive potential is connected to anodes a and cin group I23; and with relays R4 and R5 operated in register I08, thepositive potential is connected to anodes a and e in group I24. Thevarious codes for all digits of each register are as follows:

Positive potential connected to anodes Register relays operated a and d.b and d. d and e. b and e. r c and d. a and c. b and c. c and e. i a ande. a and b.

R1, R2 and R5 R4 and R5 None Normally-there is no current between theanode and cathode of'tubes I50; and H50 and no current between the anodeand cathode of the right triode of tubes I30, I40; I60 and I80, since.in each case the control'grid is negative with respect. to the cathode;but the control grid. of the left triode of each of tubes I30, I40, I60and. I- is: normally positive with respect to the cathode and there is,therefore, current between the anode and cathode of each of these.triodes. When relay I09 operates, the connection of. ground tothejunction between resistor I28. and condenser I21 causes the grid of theleft. triode of tube I30 to become less positive with respect to thecathode thereby stopping the current between the anode and cathode. The.anodeof. the left triode of tube I30 thereupon becomes more positive andso also does the. grid Oflthfi" right triode, thereby starting current.between. the anode and cathode of the right triode. The; anode of theright triode of tube I30 then becomes less positive due to the voltage.drop-in resistor I34 and condenser I33 charges through resistor I 36.When the charge on condenser I33 reaches a predetermined value, the gridof :the left triode is sufficiently positive to again start currentbetween the anode and cathode ofthe. left triode, whereby the anode ofthe left. triode becomes less positive and so. also does the grid of theright triode, thereby stopping the current-be:- tween the anode andcathode of the right triode. When the anode of the left triode. oftubel-13Il becomes more negative, at the end of the abovedescribed cycleof operation resulting. from op:- eration of the start relay I09, thegrid of the-left triode of tube I40 likewise becomes'more' negative,thereby stopping the current between. the anode and cathode. It is thefunction of tubel30. and its above-described cycle of operation to delaythe application of a start impulse to the sweep circuit. when a reordersignal is. received by tube I80, as hereinafter described but the.-delay thus introduced immediately following the operation of relay I09is without utility.

Since the beam of tube H0 is resting on the start anode I20 at the timethat the anode of the left triode of tube I30 again becomes negativefollowin operation of relay I09 as abovedescribed, a negative currentimpulse is transmitted. through anode I20 and shield electrode Hi5 to;-ground through resistor I04 in parallel with condenser I03 and the leftwinding of induction coil- I02; whereby a start signal is transmitted bythe right winding of coil I02, through'front contactsof relay IOI,conductors 2'5 and 26, back contacts: of relay 24, over the conductorsof trunk' T, through front contacts of relay 580I of the incoming.junctor 3'0, conductors 3i and 32, front contacts of relay 20I and theleft winding of induction coil 202. A start-impulse is thus trans.-mitted from the right winding of coil 202 through condenser 203, shieldelectrode 2I6, start anode. 220 on" which the beam of tube'2 I 0 isresting, conductor 2I9 and condenser 239 to-make the grid of the lefttriode of tube 240' less negative and thus start the operation of thesweep circuit SWPZ' which is similar to the sweep circuit-SW1? I. Thusthe operation ofsweep circuit SWPZ is started a: veryshort interval oftime after sweep. circuit SWP'I is started, the length of this intervalbeing the time-required for transmission of the start. impulse fromanode I20: of tube I I0 to'anod'e'220 of tube 2| 0.

Returning now'to' describe the operation of sweeps circuit'SWPI, the:-negative start: impulse,

applied to start conductor I I9 and through condenser I39 to render thegrid of the left triode of tube I40 more negative, stops the currentbetween the anode and cathode. When current stops between the anode andcathode of the left triode of tube I30, the anode becomes more positiveand so also does the grid of the right triode of tube I40, therebystarting current between the anode and cathode of the right triode. Theanode of the right triode of tube I40 thereupon becomes less positivedue to the voltage drop through resistor I44 and condenser I4I starts tocharge. At the end of a predetermined interval of time, the voltageacross condenser I4I renders the grid of the left triode of tube I40more positive to again start current between the anode and cathode ofthe left triode. The left anode of tube I40 thereupon becomes morenegative and so also the right grid thereby stopping the current betweenthe anode and cathode of the right triode. When the right grid of tubeI40 became more positive to start current through the anode and cathodeof tube I40 as above described, the grid of tube I50 and the grid of theright triode of tube I60 also become suificiently positive to startcurrent between the anode and cathode of tube I50 and to start currentbetween the anode and cathode of the right triode of tube I60. The rightanode of tube I60 thus becomes more negative and so also does the leftgrid of tube I60, thereby stopping current between the anode and cathodeof the left triod of tube I60; whereupon condenser I53 is charged in theanode-cathode circuit of tube I50. Being a pentode, the tube I50 is asubstantially constant current device and the charge on condenser I53will increase linearly with time. The voltage across condenser I53 isapplied through condenser I1I to the grid of amplifier I10, which isbiased half way to cut-01f. Since the anode of tube I10 is connectedthrough condenser I15 to the deflecting plates II5 of tube IIO, thevoltage of the deflecting plates is changed linearly to cause theelectron beam of tube IIO to sweep at a constant and desired rate fromthe start anode across each of the twenty intermediate target anodes andacross the anode I25 coming to rest on anode I26. This sweep of theelectron beam will be completed while condenser I4I is charging; andwhen the left triode of tube I40 is again energized, the right triode oftube I40 is deenergized, the right triode of tube I60 is deenergized,the left triode of tube I00 is again energized to shunt condenser I53,the grid of tube I becomes more negative, the voltage across condenser Iis restored to normal and the electron beam is restored to normalposition resting on the start anode I20.

In response to the start impulse received over trunk T and appliedthrough shield 2I6, start anode 220 of tube 2I0 and condenser 239 to thegrid of the left triode of tube 240 of sweep circuit SWPZ, the sweepcircuit SWPZ operates to sweep the electron beam of tube 2I0 from startanode 220 across the intermediate target anodes to come to rest on anode226 in the same manner that sweep circuit SWPI operates to sweep theelectron beam of tube I00 as above described. The timing of the variouscircuit elements in sweep circuit SWPZ is the same as that of thecorrespondin elements in sweep circuit SWPI so that the beam of tube 2I0sweeps over the target anodes at the same rate that the beam of tube IIOsweeps over the target anodes of tube H0. The negative start impulsereceived over trunk T while the beam of tube 2I0 is resting on targetanode 220 is also applied through condenser 232 to the grid of tube 230,thereby producing an inverted and amplified impulse in the anode-cathodecircuit; and this positive impulse is applied through condenser 235 tothe grid of the right triode of tube 280, starting current between theright anode and cathode and stopping current between the left anode andcathode. When the left triode of tube 280 is thus deenergized, the leftanode becomes positive and so also does the grid of the left triode oftube 290; thereby starting current between the left anode and cathode oftube 290. The left anode of tube 290 thereupon becomes negative and soalso does the grid of tube 296 so as to deenergize the anode-cathodecircuit of tube 296. As long as tube 296 is conducting, the anode ofthis tube is negative and so also is the battery supply conductor 229which is connected to the gas-filled tubes of each of the registers 205,206, 201 and 208; but when tube 296 is deenergized responsive to receiptof the start impulse, conductor 229 becomes positive to enable theenergization of the registers responsive to the code impulses whichfollow the start impulse.

As the beam of tube IIO successively sweeps over the five target anodesof each of groups I2I, :22, I23 and I24, a positive impulse istransmitted over trunk T each time the beam impinges on an anode onwhich a positive potential is at that time impressed, and each impulsethus transmitted will be received through coil 202 and a positivepotential impressed 0n shield electrode 2I6 when the beam of tube 2I0impinges on each of the anodes of tube 2I0 corresponding to the anodesof tube IIO on which a positive potential is impressed as controlled bythe associated re isters I05, I06, I01 and I09. The impulses thusreceived by a target anode of tube 2 I0 cause the operation of theassociated ones of registers 205, 205, 201 and 208 in hereinafterdescribed manner, to register the same digits registered in registersI05, I06, I01 and I08.

Each of the registers 205, 206, 201 and 208 is similar to the registershown in Fig. 4 and comprises five hot cathode, gas-filled dischargetubes M0, 420, 430, 440 and 450, the grid of each of which is connectedthrough an individual one of condensers 4H, 42!, HI, MI and 45I to oneof the five target anodes in one of roups 22I, 222, 223 and 224. Eachgas-filled tube controls the operation of the individually associatedone of relays M4, 424, 434, 444 and 454; and these relays in turncontrol the operation of register devices 490 to 499. If, as previouslyassumed herein, the number I319 was registered on registers I05, I06,I01 and I08, signal impulses will be received by coil 202 and betransmitted to shield 2; when the beam of tube 2I0 engages anodes a andd in group 22 I, anodes d and e in group 222, anodes b and c in group223 and anodes a and e in group 224. When the beam of tube 2I0 engagesanode a of group 22!, the received impulse is transmitted from shieldelectrode 2I6 through this anode and condenser 4 of register 205 to thegrid of gas-filled discharge tube 4I0. Tube M0 is normally biased byvoltage source EC through resistor 4I2 to be non-conducting and theother register tubes are biased in similar manner. The a positiveimpulse received and applied to the grid of tube 4I0 energizes tube M0and thereby effects the operation of relay 4I4. When the beam engagesanode d in group 22I, the received impulse is transmitted from shieldelectrode 216 through this anode and condenser Hi to tube 440. Tube 440is thereby energized and relay M4 is operated. In like manner, theimpulse received while the beam engages anode d of group 222 efiects theenergization of tube 44.?! of register 20% and the impulse receivedwhile the beam engages anode e in group 222 efiects the energization oftube 450 whereby relays 4M and 45d of register 206 are operated; theimpulses received while the beam engages anodes b and c in group 223effect the energization of tubes 420 and 430 and operation of relays 42i and 430 of register 201'; and the impulses received while the beamengages anodes a and e in group 224 effect the energization of tubes Mand 65d and operation of relays M4 and' lM in register 208.

Each one of the registers 205, 205, 207 and 208 also includes twothermionic tubes 460 and Ali! which with resistances M3, 423, 433, 453and 453, one for each gas-filled tube and with resistors 46! to and dlito il constitute a network for causing the transmission of a reordersignal in case less than two or more than two register relays areoperated and for causing the transmission of an advance signal in casetwo and only two register relays are operated. The voltages andresistors are of such values that if less than two of the relays of aregister are operated, the grid of tube 650 is positive and the grid ofthe right triode of tube 4'10 is positive, wherefore there is currentbetween the anode and cathode of the right triode and both anodes oftube 416 are negative and so also is the reorder conductor $655. If morethan two of the register relays are operated, the grid of tube 460 isnegative, tube M50 is non-conducting and consequently the grid of theleft triode of tube 410 is positive, wherefore the anodes of tube 470are negative and so also is the reorder conductor 475. If, however, twoand only two of the relays in a register are operated, the right grid oftube 310 is negative and the grid of tube $60 is positive so that theanode of tube 483 is negative and so also is the grid of the left triodeof tube 410; wherefore the anodes of tubes i'lii are positive and thereorder conductor 475 is also positive. Thus, if in each of theregisters, two and two only register relays are operated, a positivepotential will be impressed on conductor 415 and if more or less thantwo relays are operated in any of the re s ers, a negative potentialwill be impressed on conductor M5; whereby either an advance or areorder signal will be transmitted to the originating ofiice when thebeam of tube 2 i0 engages the anode 526 as hereinafter described.

When the beam of tube l it engages anode I25, a positive end-of-numbersignal impulse is transmitted over trunk T since anode I25 is connectedto the positive pole of battery B2. This end-ofnumber impulse isreceived by coil 202 and transmitted through shield electrode 216, anode225 and condenser 219 to the grid of the left triode of tube 280 of thegate circuit. The positive impulse applied to the grid of the lefttriode starts current between the left anode and cathode. This anodethen becomes more negative and with it the grid of the right triode thusdeenergizing the right triode and making the grid of the left triode oftube 290 negative; whereby current is stopped between the anode andcathode of the left triode of tube 290. If at the time that the grid ofthe left triode of tube 290 becomes negative due to receipt of apositive impulse through anode 225, reorder conductor 415 is negativebecause more or less than two gas-filled tubes and register relays havebeen operated in one or more of the registers 205, 206, 201 and 208 asabove described, then the anodes of tube 290 are positive and so also isthe grid of tube 290; whereby there is current between the anode andcathode of tube 296, battery supply conductor 229 becomes negative andthe gas-filled tubes and relays of the registers 205, 206, 201 and 208are deenergized awaiting a repetition of the signal transmission. Butif, at the time that the grid of the left triode of tube 290 becomesnegative due to receipt of a positive impulse through anode 225,conductor 415 is positive because two and only two of the gas-filledtubes and register relays have been operated in each of the registers,as above described, then the anodes of tube 293 are negative, and soalso is the grid of tube 2%; whereby tube 298 is non-conducting and theoperated gas-filled tubes and relays of registers 205, 206, 20'! and2638 remain operated until another positive start impulse is received.

If, when the beam of tube 210 engages anode 225, a negative potential isbeing applied to conductor 315 as above described, a reorder signalconsisting of a negative impulse is transmitted from conductor 22 5,through resistor 298, conductor 250, anode 228, shield 2l6, condenser203, coil 202 over trunk T through coil I02, condenser m3, shield Hi5,anode l2 and condensers I82 and 183 to the grids of tube I; but ifconductor F5 is positive at this time, an advance signal consisting of apositive impulse is transmitted over trunk T to the grids of tube I80.If a reorder signal is received and the grids of tube 80 becomenegative, current stops between the anode and cathode of the lefttriode, whereby the left anode becomes positive thus transmitting apositive impulse through condenser l3! to the start circuit and theabove-described operation of the start and sweep circuit is repeated toagain efiect the sending of the code signals as controlled by registersI05, I00, I07 and I08. If, however, an advance signal is received andthe grids of tube I80 become positive, current starts between the anodeand cathode of the right triode of tube I80 and relay I99 is operated.The operation of relay I causes the release of relay l0! therebydisconnecting coil I02 from conductors 25 and 25 and releasing relay I09whereby battery supply conductor I29 is disconnected from battery B3.The sender I00 is thereupon released and restored to normal in usualmanner.

The sender circuit 200 controls the completion of the connection fromjunctor 30 through the incoming link and line choice connector to thecalled subscriber line under the control of the registers 205, 200, 201and 208 and is thereafter restored to normal in usual manner, all asdescribed in the aforementioned patent to W. W. Carpenter.

What is claimed is:

1. In a signaling system, first and second multianode electron beamtubes each comprising electron beam emitting means, a plurality ofsecondary electron emissive target anodes, a shield electrode anddeflecting plates for controlling the beam, a line, means electricallycon necting one end of said line to the shield electrode of said firsttube, means electrically connecting the other end of said line to theshield electrode of said second tube, means associated with each of saidtubes for controlling the potential impressed on the deflectin plates tocause the electron beam to engage a first anode, and for varying thepotential applied to the deflecting for transmitting a start signalimpulse over said line when signal potential is applied to said firstanode and for transmitting a signal impulse over said line each time thebeam engages another of the anodes to which signal potential is beingapplied, means connectable to said line at said other end of the lineand including the shield electrode of said second tube responsive to theapplication of signal potential to said first anode of said first tubefor starting the sweep of the electron beam of said second tube, signalmeans at said other end of the line operatively energized in response toeach incoming signal impulse upon engagement of the electron beam ofsaid second tube with an anode corresponding to an anode of said firsttube to which a si nal potential is impressed, and register meansselectively controlled by said signal means to register a receivedsignal code.

2. In a signaling system accordin to claim 1, an additional anode incorresponding position in each of said tubes next succeeding the anodesused to transmit coded signals, means for impressing a signal potentialon said additional anode of said first tube to efiect the transmissionof an end-of-code signal when the electron beam of said first tubeengages said additional anode, and electrical means responsive to saidend-ofcode signal while the electron beam of said second tube engagessaid additional anode of said second tube.

3. In a signaling system according to claim 1, means for checking theoperation of said signal means at said other end of said line, meansrendered effective by the operation of said checking means in case theoperation of said signal means indicates receipt of no signal code otherthan any one of said difierent signal codes for applying an advancesignal potential to said last anodes of said second tube thereby toeffect the transmission of an advance signal over said line when thebeam of said second tube engages said last anode to indicate thatregistration of the transmitted coded signals has been effected, signalmeans, and means responsive to the transmission of said advance signalthrough the shield and last anode of said first tube during engagementof the beam of said first tube with said last anode to operate saidsignal means.

4. In a signaling system according to claim 1, an additional anode incorresponding position in each of said tubes next succeeding the anodesused to transmit coded signals, means for impressing a signal potentialon said additional anode of said first tube to effect the transmissionof an end-of-code signal when the electron beam of said first tubeengages said additional anode, and electrical gate means, means wherebysaid gate means responds to said end-of-code signal during the time theelectron beam of said second tube engages said additional anode of saidsecond tube, means for checking the operation of said signal means atsaid other end of aid line and for applying a reorder signal potentialto said additional anode of said second tube when the operation of saidsignal means indicates receipt of a signal other than any one of saiddifferent signal codes, means whereby said reorder signal potentialeffects the transmission of a reorder signal over said line during theengagement of the beam of said second tube with said last anode, meanswhereby indication of a signal other than any one of said difierentsignal codes causes said gate means to deenergize said signal meanswithout operating said register means, and means, including said shieldand last anode of said first tube, responsive to said reorder signalupon engagement of the beam of said first tube with said last anode forcausing the beam of said first tube to again sweep over said anodes toeffect another transmission of said start signal, said coded signal, andsaid end-of-code signal.

5. In a signaling system according to claim 1, an end-of-code anode incorresponding position in each of said tubes next succeeding the anodesused to transmit coded signals, means for impressing a signal potentialon said end-of-code anode of said first tube to effect the transmissionof an end-of-code signal when the electron beam of said first tubeengages said end-of-code anode, means for checking the operation of saidsignal means at said other end of said line and for applying a signalpotential of one character to said last anode if the operation of saidsignal means indicates receipt of no signal code other than saiddifferent signal codes and for applying a signal potential of adifierent character to said last anode if the operation of said signalmeans indicates receipt of a signal code other than any one of saiddifferent signal codes, thereby to transmit either a reorder signal oran advance signal over said line during engagement of the beam of saidsecond tube with said last anode, electrical gate means operated by saidend-of-code signal when the electron beam of said second tube engagesthe end-of-code anode, means rendered effective responsively tooperation of said gate means and controlled by said checking means toprevent operation of said register means when the operation of saidsignal means indicates receipt of a signal code other than any one ofsaid different signal codes, and signal means at said one end of theline selectively operated during engagement of the beam of said firsttube with said last anode responsive to the transmission of the one orthe other of said reorder and advance signals through the shield andlast anode of said first tube.

ROBERT O. SOFFEL.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,361,766 Hadekel Oct. 31, 1944 2,379,221 Espenchied June 26,1945 2,379,715 Hubbard July 3, 1945 2,415,870 Ryder Feb. 18, 19472,437,266 Marrison Mar. 9, 1948 2,483,400 Clark Oct. 4, 1949 2,534,369Ress Dec. 19, 1950

